In the field of graphic arts, in order to optimize the reproduction of continuous tone images or line images from a halftone image, image formation systems which exhibit ultrahigh contrast (particularly gamma of 10 or more) are required.
A known process for the formation of high contrast images comprises the use of a hydrazine derivative as disclosed in U.S. Pat. Nos. 4,224,401, 4,168,977, 4,166,742, 4,311,781, 4,272,606, and 4,211,857. In accordance with this process, ultrahigh contrast and a high sensitivity can be obtained and the addition of high concentration sulfite to the developer is allowed. Thus, the stability of the developer to air oxidation is drastically improved as compared with the lithographic developer.
However, the hydrazine compounds used in this type process have been found to have some disadvantages. That is, in order to eliminate the adverse effects of hydrazine compounds on other photographic light-sensitive materials when flowing into the developer, attempts were made to render the structure of these hydrazine compounds nondiffusive. These nondiffusive hydrazine compounds are disadvantageous in that they must be used in large amounts to provide sensitization and high contrast. When used in such large amounts, they tend to deteriorate the physical strength of the light-sensitive layers thus obtained or they tend to deposit in the coating solution. Furthermore, when a light-sensitive material comprising such a nondiffusible hydrazine compound is processed with a developer fatigued by the processing of a large amount of light-sensitive materials, it cannot provide a sufficiently high contrast.
Further, since ultrahigh contrast systems employing a hydrazine compound have heretofore required a developer having a relatively high pH value, on the order of 11.5 to 11.8, these systems are dangerous to handle and they have a high BOD or COD in waste disposal. Moreover, since large amounts of a pH buffer must be used to keep the pH value of the developer constant, the solids content of the developer is increased, making the developer sticky and difficult to wipe after it is scattered on the photographic material.
Thus, it has been desired to provide a hydrazine compound which can provide a high contrast in the presence of a developer with a lower pH value.
Moreover, light-sensitive materials for contact work commonly used in daylight may be used to make a wide variety of plate-making light-sensitive materials. In this field, a high letter image quality enabling the reproduction of fine Ming type letters has been desired. To this end, it has been desired to develop a nucleating agent having a higher activity. In particular, the nucleating agents currently in use in daylight light-sensitive materials which can be handled in daylight do not provide sufficiently higher contrast and thus a nucleating agent having an even higher activity is desired.